Search Publications
First Image of the Surface of a Star with the Hubble Space Telescope
Dupree, A. K.; Gilliland, Ronald L.
A direct image of the surface of a star, Betelgeuse (= alpha Ori; M2 Iab), has been obtained with the Faint Object Camera on the Hubble Space Telescope. Images in two ~300 A--wide bands centered at 2550 and 2800 A cover ~10 resolution elements on the stellar disk. The ultraviolet diameter of Betelgeuse of 125 +/- 5 mas at 2500 A (corresponding to …
Hubble Space Telescope Ultraviolet Imaging and Spectroscopy of the Bright Starburst in the Wolf-Rayet Galaxy NGC 4214
Robert, Carmelle; Filippenko, Alexei V.; Leitherer, Claus +3 more
We have obtained an HST Faint Object Camera ultraviolet image and Faint Object Spectrograph ultraviolet spectra of the central starburst region in the nearby amorphous galaxy NGC 4214. The ultraviolet image reveals a bright, compact, starburst knot surrounded by more than 200 fainter pointlike sources. Spectral synthesis modeling of the ultraviole…
Cometary Knots in the Helix Nebula
O'Dell, C. R.; Handron, Kerry D.
The Cometary Knots in the Helix Nebula have shown themselves in observations with the Hubble Space Telescope's WFPC2 to be well-resolved photoionized surfaces on the central star facing sides of neutral clouds. Material streams backwards from the rims of the ionized surfaces, producing tails. The neutral cores of the Cometary Knots are seen in ext…
The Hubble Space Telescope Quasar Absorption Line Key Project. VII. Absorption Systems at Z abs <= 1.3
Turnshek, David A.; Schneider, Donald P.; Savage, Blair D. +9 more
We present evidence that clumps of Lyα lines are physically associated with about half of the extensive metal-line systems (absorption systems with four or more observed metal-line species) found in this paper, demonstrate that all four Lyman-limit systems discussed here correspond to extensive metal-line absorption systems, and present an extraor…
Parallax Observations with the Hubble Space Telescope Yield the Distance to Geminga
Caraveo, Patrizia A.; Bignami, Giovanni F.; Mignani, Roberto +1 more
Using data from Hubble Space Telescope observations, we report the first optical measurement of the annual parallax of a neutron star. This is the counterpart of the X-ray/ gamma -ray pulsar Geminga, for which strong proper motion has already been reported. Significant displacement from such motion is detected using WFPC2 observations, taken at th…
Long- and short-term variability in O-star winds. I. Time series of UV spectra for 10 bright O stars.
Kaper, L.; Henrichs, H. F.; Nichols, J. S. +3 more
An atlas of time series of ultraviolet spectra is presented for 10 bright O stars. The spectra were obtained with the International Ultraviolet Explorer during seven observing campaigns lasting several days over a period of 6years. The UV P Cygni lines in 9 out of the 10 studied stars exhibit a characteristic pattern of variability in the form of …
ULYSSES plasma parameters: latitudinal, radial, and temporal variations.
Goldstein, B. E.; Neugebauer, M.; Phillips, J. L. +6 more
Observations by the Ulysses SWOOPS plasma experiment are used to investigate spatial and temporal gradients during the mission, with emphasis on more recent high latitude observations including the recent South Pole to North Pole passage during solar minimum. Compared to lower latitudes, the high latitude solar wind had higher average speed, proto…
The Final Archive and Recalibration of the International Ultraviolet Explorer (IUE) Satellite
Nichols, Joy S.; Linsky, Jeffrey L.
Since 1978 the International Ultraviolet Explorer (lUE) satellite has been acquiring the largest collection of astronomical ultraviolet spectra that will likely be obtained in the foreseeable future. The more than 100 000 spectral images, from which low and high dispersion spectra are extracted, include a very broad range of sources from solar sys…
Cepheid Calibration of the Peak Brightness of SNe Ia. V. SN 1981B in NGC 4536
Panagia, N.; Saha, A.; Labhardt, Lukas +3 more
Observations have been made with the Hubble Space Telescope between 1994 June and August over a 67 day interval, comprising 17 epochs in the F555W band and 5 epochs in the F814W band. The target was a region of an outlying spiral arm of NGC 4536 [Sbc(s)I-II), a galaxy that was parent to the type Ia supernova SN 1981B. Seventy-three Cepheids were f…
The Gas and Dust Abundances of Diffuse Halo Clouds in the Milky Way
Sembach, Kenneth R.; Savage, Blair D.
We present Goddard High-Resolution Spectrograph observations of the interstellar Mg II, Si II, P II, S II, Mn II, Cr II, Fe II, Ni II, Zn II, and Ge II lines toward HD 116852, a star at -1.3 kpc from the Galactic plane and a distance of 4.8 kpc in the direction l = 304°.9, b = -16°.1. The intermediate-resolution (FWHM ≈ 11-18 km s-1) ob…